Modern ICs have helped to integrate electronic circuitry to decrease size and cost. As a consequence, modern ICs can form complex circuitry and systems. For example, virtually all of the functionality of a system may be realized using one or a handful of ICs. Such circuitry and systems may receive and operate on both analog and digital signals, and may provide analog and digital signals.
In some situations, a circuit may use the value of an analog signal. Sometimes a S/H circuit is used to sample the level of the analog signal. The S/H circuit holds the sampled value until it is used by the circuit.
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